Generally, electric plugs have conductive blades made of, for example, metal partially embedded in an insulation housing of the plug. A portion of each of the blades is exposed for insertion and establishing electrical connection with a socket or wall outlet. Sometimes, when a plug is not fully inserted into a socket, an accidental touch to the exposed portion of the plug blade may cause an electrical shock. This is especially dangerous to children playing near the socket. Therefore, it is desirable to make a safer plug.